In a vacuum, virtual particles are constantly appearing and annihilating, is this also going on inside my vacuum cleaner?

If a nuclear explosion occuring  at an altitude of 300km  creates an EMP That would short out Most modern unshielded electronics in a 1470 km  radius area why could not one detonate one during a theoretical strike, before such missiles had made landfall, destroying their guidance electronics and  causing them to: spiral out of control and crash  into the ocean or, being aerodynamically unstable, break up  on re entry into the earth's atmosphere   

We are encouraged to generate renewable energy and to sell our surplus to the grid. A householder sells a few kWh of energy at 240v. How far away can this be used? Just on the local loop or anywwhere in the country - which would require transmission at higher voltages?

After watching Harry Potter the other day, I wondered whether it would be possible to make a working invisibility cloak. If so, any suggestions on how it woild work would be useful.

Years ago I discovered how to cut unreinforced, thick-walled rubber tubing of up to a couple of cm ID with glassily smooth ends. I have become curious about whether this was a discovery or a rediscovery, as many such things turn out to be.

I also found out how to insert glass tubes or rods into the ends of rubber tubes.

Would some of you with lab experience be willing or able to swap a few favourite techniques?

In order to open polythene bags and those A4 plastic paper sleeves you need to wet your fingers, but too wet or completely dry and your fingers can't get a grip.

"Sarah Tallon reports receiving an email from Amazon telling her: "We've noticed that customers who have purchased or rated Backyard Ballistics: Build potato Cannons, Paper match Rockets, Cincinnati Fire Kites, tennis Ball mortars, and more Dynamite Devices by William Gurstelle have also purchased Curry Easy by Madhur Jaffery. For this reason, you might like to know that Curry Easy is now available..."Just how are curries related to explo..." says Sahar as enlightenment dawns.

So ha ha... this is like a flatulence joke in a Disney movie?

I'm not buying that... computer algorithms don't have a sense of humor.

Maybe it's a British reference or sense of humor that I don't get.

Plus a page up of Backyard Ballistics at Amazon recomends many other books for me, none of them about Curry.

I have heard that the very cold temperatures we are experiecing can cause diesel to freeze. I heard that the temperature is around -12 degrees, is this true?

I have thought of this question as this can effect everybody.

I've been dropping squash balls at different temperatures from a constant height of 1m, and measuring the height they bounce up to. I understand that as you heat the squash balls, air molecules inside the ball (which has negligible increases in mass and volume) bounce again each other and the inside of the ball more often and harder, leading to more air pressure in the ball, and thus a higher bounce. Is there any equation that links pressure or temperature with a drop height and bounce height? I've been using Boyle's law, Charles law and the pressure law to find pressure, and there are existing formulae for volumes, of course, but how can I link pressure with bounce? I assume it will involve the coefficient of restitution somewhere, but I'm unsure. Thanks a lot! :)